1. Field of the Invention
The present invention relates to air pumps and more particularly, to an air passageway switchable pump head for air pump.
2. Description of the Related Art
U.S. Pat. No. 7,178,549 (equivalent to Taiwan Patent 1246568) discloses a pump head for air pump, entitled “Valve coupling device for pump”, which comprises a body including a first end, a second end, and a transverse hole between the first end and the second end, a first nozzle being mounted in the first end of the body, the first nozzle being adapted to couple with a valve of a first type, a compartment being defined in the second end of the body and including a first chamber and a second chamber, the first chamber being in communication with the transverse hole, the second chamber being in communication with the transverse hole; a switch member pivotally extending through the transverse hole of the body, the switch member including a first end and a second end and being pivotable between a first position and a second position, the switch member further including a first cam section and a second cam section, a second nozzle being mounted in the first end of the switch member and in communication with the second chamber, the second nozzle being adapted to couple with a valve of a second type different from the first type; wherein when the switch member is in the first position, the first chamber is in communication with the first nozzle under the action of the first cam section and the second chamber is blocked under the action of the second cam section; and wherein when the switch member is in the second position, the second chamber is in communication with the second nozzle under the action of the second cam section and the first chamber is blocked under the action of the first cam section.
The body of the aforesaid prior art design has a small size and is equipped with a nozzle, it is more convenient for operation when compared to a design having two holes selectively connectable to an air valve. However, the aforesaid prior art design has a complicated structure and a high manufacturing cost. Further, when operating the nozzles, the switch member may be moved accidentally, causing the chambers to be opened or closed abnormally and affecting pumping smoothness.
Therefore, it is desirable to provide a pump head or valve coupling device for air pump, which eliminates the aforesaid drawbacks.